Ash trees are medium to large trees used in landscaping. There are several varieties of ash trees, but green ash and white ash are more available in nurseries. Green ash varieties are more cold tolerant and have gold leaves in the fall while white ash trees turn purple.
According to Dr. David L. Roberts at the Michigan State University Extension, ash trees are easily identified by their opposite branching and compound leaf structure. The bark of a young ash tree is fairly smooth, while the bark of a mature ash has diamond-shaped ridges. Also, an ash leaf will have five to nine leaflets with a bud at the stem base.
Black ash trees work well in locations with adequate water. Use them for windbreaks or along stream beds. The green ash varieties can also be used for windbreaks as well as for shade trees. Since they are more drought tolerant, they can be used for highway plantings. The wood from green ash varieties is used to make furniture and baseball bats. Black ash trees produce wood suitable for firewood, baskets and barrels.
Ash trees are readily available in local nurseries. They are faster growing than some other landscape trees. Ash trees provide a habitat for birds, and the seeds are food for birds and small mammals. Pharmaceutical products are made from both green and black ash trees.
Ash trees are susceptible to snowstorm damage, especially in the spring and fall. They can also be infested with a variety of insects, including the Ash Borer which can kill the tree. The Emerald Ash Borer is a type of wood-boring insect. The larvae develop below the bark of ash trees where they feed on the cambium layer, depriving the tree of nutrients. The host tree dies within three to five years of infestation. Because the pest first appears at the top of the tree, its presence is hard to detect in the first year of infestation.
Treatment and Prevention
According to experts at the North Central IPM Center, "If a tree has lost more than 50 per cent of its canopy, it is probably too late to save the tree." If the tree can be saved, there are four categories of insecticides to use for treatment or prevention of an Emerald Ash Borer infestation. Two are applied by injection into either the soil or trunk of the tree, and two are sprayed either on the trunk, branches, or leaves. Do not transport ash wood as the insect can also be spread by moving infested logs.